SharingPtr.cpp
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//===---------------------SharingPtr.cpp ------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "lldb/Utility/SharingPtr.h"
#if defined(ENABLE_SP_LOGGING)
// If ENABLE_SP_LOGGING is defined, then log all shared pointer assignments and
// allow them to be queried using a pointer by a call to:
#include <assert.h>
#include <execinfo.h>
#include "llvm/ADT/STLExtras.h"
#include <map>
#include <mutex>
#include <vector>
class Backtrace {
public:
Backtrace();
~Backtrace();
void GetFrames();
void Dump() const;
private:
void *m_sp_this;
std::vector<void *> m_frames;
};
Backtrace::Backtrace() : m_frames() {}
Backtrace::~Backtrace() {}
void Backtrace::GetFrames() {
void *frames[1024];
const int count = ::backtrace(frames, llvm::array_lengthof(frames));
if (count > 2)
m_frames.assign(frames + 2, frames + (count - 2));
}
void Backtrace::Dump() const {
if (!m_frames.empty())
::backtrace_symbols_fd(m_frames.data(), m_frames.size(), STDOUT_FILENO);
write(STDOUT_FILENO, "\n\n", 2);
}
extern "C" void track_sp(void *sp_this, void *ptr, long use_count) {
typedef std::pair<void *, Backtrace> PtrBacktracePair;
typedef std::map<void *, PtrBacktracePair> PtrToBacktraceMap;
static std::mutex g_mutex;
std::lock_guard<std::mutex> guard(g_mutex);
static PtrToBacktraceMap g_map;
if (sp_this) {
printf("sp(%p) -> %p %lu\n", sp_this, ptr, use_count);
if (ptr) {
Backtrace bt;
bt.GetFrames();
g_map[sp_this] = std::make_pair(ptr, bt);
} else {
g_map.erase(sp_this);
}
} else {
if (ptr)
printf("Searching for shared pointers that are tracking %p: ", ptr);
else
printf("Dump all live shared pointres: ");
uint32_t matches = 0;
PtrToBacktraceMap::iterator pos, end = g_map.end();
for (pos = g_map.begin(); pos != end; ++pos) {
if (ptr == NULL || pos->second.first == ptr) {
++matches;
printf("\nsp(%p): %p\n", pos->first, pos->second.first);
pos->second.second.Dump();
}
}
if (matches == 0) {
printf("none.\n");
}
}
}
// Put dump_sp_refs in the lldb namespace to it gets through our exports lists
// filter in the LLDB.framework or lldb.so
namespace lldb {
void dump_sp_refs(void *ptr) {
// Use a specially crafted call to "track_sp" which will dump info on all
// live shared pointers that reference "ptr"
track_sp(NULL, ptr, 0);
}
}
#endif
namespace lldb_private {
namespace imp {
shared_count::~shared_count() {}
void shared_count::add_shared() {
#ifdef _MSC_VER
_InterlockedIncrement(&shared_owners_);
#else
++shared_owners_;
#endif
}
void shared_count::release_shared() {
#ifdef _MSC_VER
if (_InterlockedDecrement(&shared_owners_) == -1)
#else
if (--shared_owners_ == -1)
#endif
{
on_zero_shared();
delete this;
}
}
} // imp
} // namespace lldb